<?php
for ($i = 0; $i < 5; $i++) {
    $client = new swoole_client(SWOOLE_SOCK_TCP | SWOOLE_KEEP, SWOOLE_SOCK_SYNC);
    $client->connect('127.0.0.1', 3333);
    $client->send("hello world");
    echo $client->recv() . PHP_EOL;
    $client->close();
}